TY  - JOUR
AB  - Exclusive production of the isoscalar vector mesons $\omega$ and $\phi$ is measured with a 190 GeV$/c$ proton beam impinging on a liquid hydrogen target. Cross section ratios are determined in three intervals of the Feynman variable $x_{F}$ of the fast proton. A significant violation of the OZI rule is found, confirming earlier findings. Its kinematic dependence on $x_{F}$ and on the invariant mass $M_{p\mathrm{V}}$ of the system formed by fast proton $p_\mathrm{fast}$ and vector meson $V$ is discussed in terms of diffractive production of $p_\mathrm{fast}V$ resonances in competition with central production. The measurement of the spin density matrix element $\rho_{00}$ of the vector mesons in different selected reference frames provides another handle to distinguish the contributions of these two major reaction types. Again, dependences of the alignment on $x_{F}$ and on $M_{p\mathrm{V}}$ are found. Most of the observations can be traced back to the existence of several excited baryon states contributing to $\omega$ production which are absent in the case of the $\phi$ meson. Removing the low-mass $M_{p\mathrm{V}}$ resonant region, the OZI rule is found to be violated by a factor of eight, independently of $x_\mathrm{F}$.
DA  - 2014
DO  - 10.1016/j.nuclphysb.2014.07.020
LA  - eng
M2  - 1078
PY  - 2014
SN  - 0550-3213
SP  - 1078-1101
T2  - Nuclear Physics B
TI  - Spin alignment and violation of the OZI rule in exclusive ω and ϕ production in pp collisions
UR  - https://nbn-resolving.org/urn:nbn:de:0070-pub-26879112
Y2  - 2024-11-21T19:40:57
ER  -